package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisData;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.CacheClient.tryLock;
import static com.hmdp.utils.CacheClient.unlock;
import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private CacheClient cacheClient;

    @Resource
    private  StringRedisTemplate stringRedisTemplate;
    /**
     * 根据id查询商铺信息
     * @param id 商铺id
     * @return 商铺详情数据
     */
    @Override
    public Result queryById(Long id) {
       //缓存穿透
        Shop shop=cacheClient
               .queryWithPassThrough(CACHE_SHOP_KEY,id,Shop.class,this::getById,CACHE_SHOP_TTL,TimeUnit.MINUTES);
        //互斥锁解决缓存击穿
        //Shop shop = queryWithMutex(id);
        //逻辑过期了热点数据缓存击穿
        //Shop shop = CacheClient
          //      .queryWithLogicalExpire(CACHE_SHOP_KEY,id,Shop.class,this::getById,20L,TimeUnit.SECONDS);
        if (shop == null) {
            return Result.fail("店铺不存在！");
        }
        //返回
        return Result.ok(shop);
    }


    /*private static final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);
*/
   /* //逻辑过期了热点数据缓存击穿
    public Shop queryWithLogicalExpire(Long id){
        //缓存穿透的解决方案
        String key=CACHE_SHOP_KEY + id;
        //从redis查缓存
        String shopJson= stringRedisTemplate.opsForValue().get(key);
        //判断是否存在
        if(StrUtil.isNotBlank(shopJson)){
            //存在，直接返回
            return null;
        }
        //4.命中，需要先把json反序列化为对象
        RedisData redisData=JSONUtil.toBean(shopJson,RedisData.class);
       Shop shop=JSONUtil.toBean((JSONObject) redisData.getData(),Shop.class);
        LocalDateTime expireTime=redisData.getExpireTime();
        //5.判断是否存在过期
        if(expireTime.isAfter(LocalDateTime.now())){
            //5.1未过期
            return shop;
        }
        //6.已经过期
        //缓存重建
        //获取互斥锁
        String lockKey=LOCK_SHOP_KEY+id;
        boolean isLocked=tryLock(lockKey);
        //判断是否获取成功
        if(isLocked){
            //成功，开启独立线程，实现缓存建立
            CACHE_REBUILD_EXECUTOR.submit(()->{
                try {
                    //创建这个缓存
                    this.saveShop2Redis(id,20L);
                } catch (Exception e) {
                    throw new RuntimeException(e);
                } finally {
                    //释放锁
                    unlock(lockKey);
                }
            });
        }


        //6.4返回过期的商铺信息


        return shop;
    }
*/



/*//互斥锁解决击穿
    public Shop queryWithMutex(Long id){
        //缓存穿透的解决方案
        String key=CACHE_SHOP_KEY + id;
        //从redis查缓存
        String shopJson= stringRedisTemplate.opsForValue().get(key);
        //判断是否存在
        if(StrUtil.isNotBlank(shopJson)){
            //存在，直接返回
            return JSONUtil.toBean(shopJson, Shop.class);
        }
        //命中空值
        if(shopJson!=null){
            //返回错误信息
            return null;
        }
        //4.实现缓存重建
        //4.1获取互斥锁
         String   lockkey = "lock:shop"+id;
         Shop shop=null;
        try {
            boolean isLock= tryLock(lockkey);
            //4.2判断是否成功获取
            if(!isLock){
                //4.3失败休眠
                Thread.sleep(50);
                queryWithMutex(id);
            }
            //4.4成功，根据id查询数据库
            shop = getById(id);
            //模拟重建延时
            Thread.sleep(200);
            //5.不存在，返回错误
            if(shop==null){
                //设置空值在redis
                stringRedisTemplate.opsForValue().set(key, "",CACHE_NULL_TTL, TimeUnit.MINUTES);
                return null;
            }
            //6.存在，写入redis
            stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        } finally {//7.释放互斥锁
            unlock(lockkey);
        }
        //返回
        return shop;
    }*/

    //缓存穿透的解决方案 空值，布隆
    /*public Shop queryWithPassThrough(Long id){
        String key=CACHE_SHOP_KEY + id;
        //从redis查缓存
        String shopJson= stringRedisTemplate.opsForValue().get(key);
        //判断是否存在
        if(StrUtil.isNotBlank(shopJson)){
            //存在，直接返回
            return JSONUtil.toBean(shopJson, Shop.class);
        }
        //命中空值
        if(shopJson!=null){
            //返回错误信息
            return null;
        }
        //不存在，根据id查询数据库
        Shop shop=getById(id);
        //不存在，返回错误
        if(shop==null){
            //设置返回空值
            stringRedisTemplate.opsForValue().set(key, "",CACHE_NULL_TTL, TimeUnit.MINUTES);

            return null;
        }
        //存在，写入redis
        stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);
        //返回
        return shop;
    }*/


   /*//锁
    private boolean tryLock(String key){
        Boolean flag=stringRedisTemplate.opsForValue().setIfAbsent(key, "1",10, TimeUnit.SECONDS);
          return BooleanUtil.isTrue(flag);
    }

    private void unlock(String key){
        stringRedisTemplate.delete(key);
    }

    //永久有效，真正过期是我们逻辑有效
    public void saveShop2Redis(Long id,Long expireSeconds) throws InterruptedException {
        //1.查询店铺数据
        Shop shop=getById(id);
       Thread.sleep(200);
        //2.封装逻辑过期时间
        RedisData redisData=new RedisData();
        redisData.setData(shop);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));
        //3.写入redis
        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id,JSONUtil.toJsonStr(redisData));
    }*/


    /**
     * 更新商铺信息
     *  shop
     *
     */
    @Override
    @Transactional
    public Result update(Shop shop) {
       Long id=shop.getId();
       if(id==null){
           return Result.fail("店铺id不能为空！");
       }
        //更新数据库
        updateById(shop);
        //删除缓存
        stringRedisTemplate.delete(CACHE_SHOP_KEY+id);
        return Result.ok();
    }
}
